It is usual that a greenhouse have outside walls made of glass panels. The glass panels are transparent and transmit sunlight through the panel making light and heat available to the plants on the interior of the greenhouse. The glass panels are also sufficiently rigid and give strength to the structure.
For holding the glass panels in place on the ceiling and side walls it is customary to provide metallic rails. These rails are arranged in spaced parallel relation along the ceiling and also on the sides of the greenhouse. This type of structure bears some resemblance to the use of rafters and studs in wood buildings. The rails bear resemblance also to I-beams. The glass panels are held and supported at their edges between the rails, with the edges of the glass panels being held by suitable attachment means to the upper portions of the rails. The rails are made of metal such as steel or aluminum and have a form similar to an I-beam so as to provide structural strength necessary for such a building. These metallic rails are good conductors of heat and their surfaces are exposed to the outside atmosphere and the interior of the greenhouse. A difficulty in the use of the structures just described has been that condensation forms on the metallic surfaces and drips or has to be carried away in some manner. Some manufacturers have designed their rails to provide troughs at the lower portion of the rails, to catch the condensation and to carry it away longitudinally of the rail.
It is an object of this invention to provide materials and methods of assembly which will give better insulation and avoid condensation that has attended prior greenhouse structures. Another object is to provide a structure which makes a thermal barrier to the passage of exterior temperature into the interior of the greenhouse. Yet another object is to provide a method by which the materials may be assembled easily and quickly, without difficulty. Further it is desired to provide such a method which can be utilized on location in connection with a presently existing greenhouse.